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000
FXUS66 KPQR 070506
AFDPQR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
905 PM PST FRI DEC  6 2013

.SYNOPSIS...THE LOW PRESSURE SYSTEM RESPONSIBLE FOR THE SNOW EARLIER
TODAY HAS MOVED ONSHORE AND IS NOW NEAR MEDFORD. STRONG HIGH PRESSURE
BUILDING DOWN THE EAST SLOPES OF THE CASCADES CONTINUES TO GENERATE
FRIGID EAST WINDS ACROSS THE GREATER PORTLAND AND VANCOUVER METRO
AREA. WIND CHILLS REMAIN DOWNRIGHT DANGEROUS IN THE HIGHER TERRAIN.
VERY COLD AIR...THE COLDEST IN FOUR YEARS...WILL SETTLE INTO THE
FORECAST AREA TONIGHT AND LINGER THROUGH THE WEEKEND. SLOW RECOVERY
TOWARD NORMAL TEMPERATURES WILL BEGIN NEXT WEEK...BUT MAY OR MAY NOT
BE FAST ENOUGH TO MITIGATE A SIGNIFICANT SNOW OR ICE EVENT FOR THE
INTERIOR LOWLANDS LATER NEXT WEEK.

&&

.SHORT TERM...TONIGHT THROUGH MONDAY...MAIN CHANGES TO THIS EVENINGS
FORECAST PACKAGE WILL CENTER AROUND CANCELING THE WIND ADVISORY FOR
THE PORTLAND AND VANCOUVER METRO AREA...AS WINDS ARE BREEZY BUT WELL
BELOW ADVISORY CRITERIA OF 45 MPH. WILL REPLACE THIS WITH A SPECIAL
WEATHER STATEMENT HIGHLIGHTING WIND CHILLS IN THE COLUMBIA GORGE AND
THE GREATER PORTLAND AND VANCOUVER METRO AREA. ALL WINTER WEATHER
ADVISORIES AND WARNINGS HAVE ENDED...ASIDE FROM THE WIND CHILL
WARNING FOR THE CASCADES. SNOW AMOUNTS TODAY RANGED FROM JUST A TRACE
ACROSS PORTIONS OF THE PORTLAND METRO AREA TO GENERALLY 4-6 INCHES
ACROSS THE SOUTH WILLAMETTE VALLEY. CORVALLIS AND PHILOMATH WERE THE
BIG WINNERS WITH 9 INCHES OF SNOW FROM THIS SYSTEM.

WITH BREEZY CONDITIONS LIKELY TO CONTINUE MUCH OF THE NIGHT...
DECIDED TO BUMP UP THE FCST LOW TEMPS TONIGHT IN MANY AREAS. THERE
SHOULD REMAIN ENOUGH MIXING AND CLOUD COVER TONIGHT TO KEEP TEMPS UP
IN THE TEENS FOR THE LOWLANDS. THE BEST CHANCE FOR TEMPS TO BOTTOM
OUT WILL LIKELY BE IN THE KELSO AND LOWER COLUMBIA AREA...AS SKIES
ARE ALREADY CLEARING.

ANOTHER COLD DAY IS ON TAP FOR SATURDAY...THOUGH INCREASING SUNSHINE
SHOULD TAKE A LITTLE BIT OF THE EDGE OFF THE MIDDAY TEMPS IN THE 20S
FOR THE LOWLANDS. AREAS NEAR THE COLUMBIA GORGE WILL CONTINUE TO SEE
BREEZY CONDITIONS WITH WIND CHILLS IN THE SINGLE DIGITS AT TIMES.
WITH TEMPERATURES THIS COLD SNOW WILL NOT MELT OUTSIDE OF THE
SUNSHINE...THE BEST CHANCE FOR SNOW TO DISAPPEAR WILL BE SUBLIMATION
DUE TO THE VERY DRY AIR MASS. AREAS WITH GREATER THAN 1 INCH OF SNOW
ON THE GROUND WILL PROBABLY MAINTAIN THEIR SNOW COVER HEADING INTO
SATURDAY NIGHT.

SATURDAY NIGHT APPEARS TO BE THE COLDEST NIGHT FOR MOST AREAS AS
OFFSHORE FLOW WEAKENS OUTSIDE OF THE IMMEDIATE COLUMBIA GORGE AREA.
WITH CLEAR SKIES...DEWPOINTS IN THE SINGLE DIGITS...AND WINDS MUCH
CALMER...THE STAGE WILL BE SET FOR OPTIMAL RADIATIONAL COOLING. THIS
WILL ESPECIALLY BE THE CASE IN SHELTERED AND SNOW-COVERED VALLEY
LOCATIONS. OUTLYING AREAS AROUND EUGENE AND CORVALLIS COULD TAKE A
SHOT AT THE ZERO DEGREE MARK EARLY SUNDAY MORNING IF ALL GOES RIGHT.
SOME OF THE SHELTERED COAST RANGE AND CASCADE VALLEYS COULD GET BELOW
ZERO. OVERALL THE COLDEST NIGHT IN QUITE SOME TIME.

THERE IS THE POTENTIAL FOR FREEZING FOG TO DEVELOP IN THE SOUTH
WILLAMETTE...NEHALEM RIVER...AND HOOD RIVER VALLEYS SUN AND MON
MORNINGS...WHICH COULD HOLD TEMPS DOWN IN THE LOWER 20S FOR HIGHS.
OTHERWISE SUNDAY AND MONDAY WILL BE PARTLY TO MOSTLY SUNNY WITH HIGHS
STILL UNLIKELY TO BREAK THE FREEZING MARK AWAY FROM THE COAST. A WEAK
DISTURBANCE DROPPING DOWN THE BC COAST MON WILL HAVE TO BE WATCHED
FOR THE POSSIBILITY OF SPREADING SOME LIGHT SNOW INTO OUR NORTHERN
ZONES AS EARLY AS MONDAY EVENING.  WEAGLE

.LONG TERM...MONDAY NIGHT THROUGH FRIDAY. MID RANGE MODELS HAVE BEEN
CONSISTENT ON FORECASTING LIGHT PRECIPITATION MONDAY NIGHT INTO
TUESDAY MORNING AS A WEAK DISTURBANCE DROPS SOUTH ALONG THE WEST
COAST. MODELS SUGGEST WARMING AHEAD OF THE PRECIPITATION...BUT THINK
THE WELL ESTABLISHED ARCTIC AIR WILL BE MORE DIFFICULT TO WARM THAN
THE MODELS SUGGEST...AND AM CURRENTLY FORECASTING TEMPERATURES BELOW
GUIDANCE FOR MONDAY NIGHT AND TUESDAY. THEREFORE...FREEZING RAIN...
SNOW...RAIN...OR SOME MIX OF THE ABOVE IS POSSIBLE MONDAY NIGHT INTO
TUESDAY MORNING.

A WARM FRONT WILL CLIP THE NORTHWEST OREGON/SOUTHWEST WASHINGTON
TUESDAY NIGHT BEFORE A SERIES OF MOISTER AND MILDER FRONTS MOVE
ACROSS THE REGION. TEMPERATURES WILL WARM AND EXPECT SNOW LEVELS TO
RISE NEAR THE CASCADE PASS LEVELS WITH THESE SYSTEMS. DIFFERENCES
BETWEEN THE VARIOUS MODELS MAKE IT DIFFICULT TO HONE IN ON THE TIMING
OF THE BANDS OF PRECIPITATION...BUT GENERALLY EXPECT HEAVY RAIN AND
MOUNTAIN SNOW AT TIMES BETWEEN WEDNESDAY AND FRIDAY...AND GUSTY WINDS
ALONG THE COAST.  HARTLEY

&&

.AVIATION...MAINLY WIDESPREAD VFR CONDITIONS PREVAIL WITH CIGS
AROUND 6000-8000 FT. MVFR CIGS NEAR 2500 FT LINGER THROUGH 06Z
OVER THE SOUTH WILLAMETTE VALLEY BEFORE LIFTING TO VFR. GUSTY EAST
WINDS WILL CONTINUE THROUGH THE COLUMBIA RIVER GORGE AND ACROSS
THE PORTLAND METRO AREA TONIGHT...EASING BY EARLY SATURDAY
MORNING.

KPDX AND APPROACHES...VFR CONDITIONS WITH CIGS AROUND 8K-10K FT.
EAST WINDS WITH GUSTS NEAR 25 TO 30 KT PERSIST OVERNIGHT...EASING
AROUND 14-18Z SATURDAY MORNING. /27

&&

.MARINE...GUSTY E TO NE WINDS WILL GRADUALLY SUBSIDE
OVERNIGHT...WITH SOME GUSTS TO 25 KT LINGERING OVER THE OUTER
CENTRAL WATERS MIDDAY SATURDAY. SQUARE SEAS OF 5-6 FT AT 5-6
SECONDS WILL CONTINUE THROUGH ABOUT 12Z SATURDAY...BEFORE LONGER
PERIOD SWELL ARRIVES LATER SATURDAY MORNING.

OTHERWISE...EXPECT RELATIVELY BENIGN WEATHER SATURDAY THROUGH
TUESDAY. A STRONGER LOW PRESSURE SYSTEM MAY IMPACT THE REGION
TOWARDS THE MIDDLE OF NEXT WEEK...BUT DECENT UNCERTAINTY EXISTS IN
THE TIMING AND STRENGTH OF THE WINDS. SOUTHERLY GALES APPEAR AT
LEAST POSSIBLE. /NEUMAN

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...WIND CHILL WARNING UNTIL NOON PST SATURDAY FOR CASCADES IN LANE
     COUNTY-NORTHERN OREGON CASCADES.

WA...WIND CHILL WARNING UNTIL NOON PST SATURDAY FOR SOUTH WASHINGTON
     CASCADES.

PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 6 AM PST SATURDAY FOR
     COASTAL WATERS FROM CAPE SHOALWATER TO FLORENCE OUT 60 NM.

     SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 AM PST SATURDAY
     FOR COASTAL WATERS FROM CAPE SHOALWATER TO CASCADE HEAD OUT
     60 NM.

&&

$$


MORE WEATHER INFORMATION ONLINE AT..
    HTTP://WEATHER.GOV/PORTLAND


INTERACT WITH US VIA SOCIAL MEDIA
    WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.PORTLAND.GOV
    WWW.TWITTER.COM/NWSPORTLAND

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.